The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A229710 Least m of maximal order mod n such that m is a sum of two squares. 2
 2, 5, 5, 5, 2, 13, 2, 5, 2, 5, 2, 5, 5, 5, 2, 13, 2, 13, 5, 5, 2, 37, 2, 5, 2, 13, 13, 5, 2, 5, 2, 5, 2, 13, 2, 13, 13, 5, 5, 13, 2, 5, 5, 5, 5, 13, 5, 37, 2, 5, 2, 5, 2, 37, 2, 13, 2, 13, 2, 5, 2, 5, 2, 5, 2, 17, 13, 5, 5, 5, 2, 13, 2, 37, 29, 13, 2, 13, 2, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 5,1 COMMENTS The sequence is undefined at n=4, as all the primitive roots are congruent to 3 mod 4. Terms are not necessarily prime. For example, a(109) = 10. a(prime(n)) = A229709(n). LINKS Eric M. Schmidt, Table of n, a(n) for n = 5..10000 Christopher Ambrose, On the Least Primitive Root Expressible as a Sum of Two Squares, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 13, Paper A55, 2013. EXAMPLE The integer 5 = 2^2 + 1^2 has order 2 mod 12, the maximum, so a(12) = 5. PROG (Sage) def A229710(n) : m = Integers(n).unit_group_exponent(); return 0 if n==1 else next(i for i in PositiveIntegers() if mod(i, n).is_unit() and mod(i, n).multiplicative_order() == m and all(p%4 != 3 or e%2==0 for (p, e) in factor(i))) CROSSREFS Cf. A001481, A111076, A229708, A229709. Sequence in context: A116698 A246900 A277086 * A240947 A023398 A186501 Adjacent sequences:  A229707 A229708 A229709 * A229711 A229712 A229713 KEYWORD nonn AUTHOR Eric M. Schmidt, Sep 27 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 13 12:57 EDT 2021. Contains 344997 sequences. (Running on oeis4.)